Chassis component with a rotary damper

ABSTRACT

A chassis component has a rotary damper with a housing, a damper shaft rotatably accommodated thereat, a displacing device in the housing, and a magnetic field source. The displacing device has a damper volume with magnetorheological fluid to influence the damping of the rotary motion of the damper shaft relative to the housing. The damper volume is divided into variable chambers by a partition wall connected with the housing and a partition wall connected with the damper shaft. Radial and axial gaps are formed between the partition walls, the damper shaft and the housing. The magnetic field source has a controllable electric coil for influencing the strength of the magnetic field and thus the strength of damping. A substantial part of the magnetic field of the magnetic field source passes through the gaps and influences the gap sections in dependence on the strength of the magnetic field.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a chassis component with a rotarydamper, the rotary damper comprising a housing and a damper shaftrotatably accommodated thereat and a displacing device in the housing.In the housing a damper volume comprising magnetorheological fluid isprovided as a working fluid for influencing the damping of the rotary orpivoting motion of the damper shaft relative to the housing.

A great variety of chassis components has been disposed in the prior artcomprising a linear damper or a rotary damper or rotation damper. Thesechassis components allow damping a relative motion. In particular in thecase that the required or available travel path or rotation angle orpivot angle is limited at the chassis component or the chassis componentper se, many of the known chassis components are not sufficientlyflexible in application or the required braking momentum or the requiredbraking force is too weak or the required rotational speeds are too highso that the braking momentum cannot be varied or set at all or not asfast as required.

Rotation dampers involving oil and external control valves are priorart. Minimum space requirement of chassis components is of considerableadvantage in modern vehicles. This means that the active surfaces aresmall and this is why the working pressure must be increased (100 barand more) for generating suitable surface pressures and thus, forces ormoments. A drawback of these actuators is that the parts moving relativeto one another must be manufactured with high precision so the gaps mustprovide for the lowest possible pressure loss. Since this tends toinclude inner contours and rectangular or deformed components/sealingedges which must preferably be ground to achieve good tolerances/gaps,very high costs are involved. Given these contours, pressures,alternatively attaching sealing members likewise involves lots of workand costs. Sealing the edges or transitions e.g. between axial andradial contours is particularly difficult. Moreover, seals lead to highbase frictions or base friction forces and moments.

U.S. Pat. No. 6,318,522 B1 has disclosed a stabilizer comprising arotation damper with magnetic seals for a motor vehicle. The stabilizercomprises two rotation dampers, each rotation damper comprising a shaftwith two lobes (vanes) extending outwardly each. The shaft may swivelwith the vanes wherein the swiveling angle is limited by wedge-shapedguide plates extending radially inwardly in the housing. Between theoutwardly protruding vanes and the guide plates the housing is providedwith hollow spaces or chambers two of which increase during theswiveling motion of the shaft while the other two are reducedaccordingly. The chambers contain magnetorheological fluid. The radiallyinwardly ends of the guide plates and the radially outwardly and axiallyoutwardly ends of the vanes show magnets disposed thereon which due totheir magnetic field seal the radially inwardly, radially outwardly andaxial gaps to restrict the leakage flow. This prevents abrasions fromthe otherwise contacting seals between the chambers, increasing theirservice life. The actual damping of the stabilizer is provided by boresin the guide plates interconnecting conjugate chambers. The borescontain spring-biased ball valves which open up the flow path as thedifferential pressure in the two chambers exceeds the preset springforce. U.S. Pat. No. 6,318,522 B1 thus provides a low-maintenancestabilizer which works reliably per se. There is the drawback of aconsiderable base friction since the gap sealing is designed for theintended damping force. Another drawback is that the damping force isinvariable.

DE 10 2013 203 331 A1 has disclosed the use of magnetorheological fluidfor damping relative motions between vehicle wheels and vehicle bodiesin vehicles. A gear stage comprising multiple interacting gear wheels isprovided. The gear stage is filled with magnetorheological fluid. Thedrain from the gear stage is directed to an external valve where amagnetic field acts on the magnetorheological fluid before the fluid isguided to return to the inflow of the housing. The drawback is that thehousing with the gear stage is filled with magnetorheological fluid.Magnetorheological fluid is a suspension of magnetically polarizableparticles (carbonyl ferrous powder) finely distributed in a carrierliquid and showing diameters between approximately 1 micrometer and 10μm. This is why all the gaps between components moving relative to oneanother (axial gaps between the rotating gear wheel and the housing,radial gaps between the tooth flank and the housing interior bores, andalso gaps between the contacting/meshing tooth profiles in the gearstage) must be larger than the largest of the magnetic particles. Forpractical purposes the gaps must even be multiple times larger becauseeven absent a magnetic field the particles may accumulate to form largeclusters or under the influence of a magnetic field, links and thuslarge carbonyl ferrous units may build up. An unsuitable gap results injamming/seizing, or the (coated) particles are pulverized and thususeless. The significant drawback thereof is that these mandatorilyrequired gaps result in very strong leakage flow in particular ifpressures exceeding 100 bar are to be achieved. This prohibits highlyeffective damping. In order to achieve high damping values all of thegaps must be sealed which involves much work, is expensive, and in somecases may be technically impossible. Thus for example a rolling-off gapbetween the two involute tooth profiles is virtually impossible to seal.A high-pressure-tight sealing of a gear wheel showing a complex shape inconjunction with ferrous liquids is economically unfeasible in massproduction. If the gaps are to be sealed by means of magnets as is knownfrom U.S. Pat. No. 6,318,522 B1, the damping of weaker forces would notwork satisfactorily due to the high base friction. Due to the high basemomentum only large rotational forces can be damped with agreeableresponsivity. This is why the structural principle in DE 10 2013 203 331A1 in conjunction with magnetorheological fluids is not suitable formanufacturing inexpensive chassis components capable of being damped andshowing flexibility of adjustment for damping high forces or moments.

SUMMARY OF THE INVENTION

It is therefore the object of the present invention to provide an inparticular inexpensive chassis component with a damper which enablesflexibility in setting the damping and allows satisfactorily dampinghigh and in particular also weak forces and rotational forces. Thechassis component is in particular intended to be simple in structure.

This object is solved by a chassis component showing the features asclaimed. Preferred specific embodiments of the invention are thesubjects of the dependent claims. Further advantages and features of thepresent invention can be taken from the general description and thedescription of the exemplary embodiments.

A chassis component according to the invention comprises onerespectively at least one rotary damper and includes a housing and adamper shaft rotatably accommodated thereat, a displacing device in thehousing and at least one magnetic field source. The displacing devicehas a damper volume with magnetorheological fluid as a working fluid bymeans of which it can operate to influence the damping of the rotarymotion of the damper shaft relative to the housing. The displacingdevice comprises at least two partition units which subdivide the dampervolume or a damper volume in the damper housing into at least twovariable chambers, at least one of the partition units comprising apartition wall connected with the housing. At least one of the partitionunits comprises a partition wall connected with the damper shaft and maypreferably be configured as a swiveling vane. In the radial direction a(first) (radial) gap section or gap is configured between the partitionunit connected with the housing and the damper shaft. The first gapsection substantially extends in the axial direction. In the radialdirection another (or a second) (radial) gap section is configuredbetween the partition unit connected with the damper shaft and thehousing. The other or second gap section extends at least over aconsiderable portion in the axial direction. In the axial direction atleast one more (or a third) (axial) gap section is configured betweenthe partition unit connected with the damper shaft and the housing. This(i.e. the third gap section) extends at least over a considerableportion in the radial direction. At least a substantial part of themagnetic field of the magnetic field source passes through at least twoof the indicated gap sections. The magnetic field source comprises atleast one controllable electric coil for influencing the strength of themagnetic field. Thus, the strength of damping and preferably also thestrength of sealing is influenced. In particular a substantial part ofthe magnetic field of the magnetic field source passes through at leastthe two gap sections, simultaneously influencing at least the two gapsections in dependence on the strength of the magnetic field.

Each gap section may be configured as a separate gap or two or more gapsections may be part of one shared gap.

Each gap section shows a direction of extension or direction of curveand a gap height transverse to the direction of curve. A purely axialgap section extends in the radial direction and/or the peripheraldirection. The gap height extends in the axial direction. A purelyradial gap section extends in the axial direction and optionally also inthe peripheral direction.

Then the first and the second gap sections particularly preferablysubstantially extend in the axial direction while the gap heightssubstantially extend in the radial direction. The third gap section isparticularly preferably configured as an axial gap section so that thegap height substantially extends in the axial direction. The gapsection, however, substantially extends in the radial direction and/orin the peripheral direction.

The gaps or gap sections may each be linear in configuration.Alternately each gap section may show one or more bends or may consistof bent gap regions only.

The chassis component according to the invention has many advantages. Aconsiderable advantage of the chassis component according to theinvention consists in the fact that two or more gap sections andpreferably all of the gap sections are sealed as required by means ofthe magnetic field of the magnetic field source. This allows toconfigure the gaps or gap sections to show a sufficient gap height toprovide a weak base friction. While the magnetic field is active, a highlevel of sealing continues to be achieved so as to enable high dampingvalues. It is not necessary to chose a particularly low gap height toprevent leakage. Leakage is not prevented by means of the gap dimensions(gap height) but by means of magnetic sealing. An adjustable strength ofthe magnetic field allows to adaptively accommodate the dampingstrength.

The controllable electric coil allows flexibility in setting a magneticfield to the desired strength. In this way a damping at the desiredstrength is set. At the same time, in this way in particular thestrength of sealing is set for at least two gaps and in particular allthe radial and axial gaps. The base friction is weak while the magneticfield is weak, and sealing is strong while the relative pressure or therotational force is strong. Thus, the dynamics provided can be muchhigher than in the prior art since not only the damping proper isinfluenced but so is the sealing.

In fact, a braking momentum acts which is additively combined from theexisting base momentum and the damping momentum. Both the base momentumand damping momentum are influenced by the effective (temporallydependent and temporally controllable) magnetic field. In the case ofweak forces and moments to be damped, a weaker force of the magneticfield generates a weaker base friction (base momentum). In the case ofstronger forces and moments to be damped, a stronger force of themagnetic field generates a stronger base friction (base momentum). Astronger base momentum does not show any adverse effects on responsivityif a correspondingly stronger braking momentum is given. In particularthe ratio of the braking momentum to a base momentum in a mediumoperating range (in particular exactly in the middle) is higher than 2:1and preferably higher than 5:1 and particularly preferably higher than10:1.

For conventional seals in pure oil circuits the gap dimension chosenmust be particularly small for obtaining a high level of sealing. Thissimultaneously also results in a high base momentum in idling andcorrespondingly high wear to the seals. This is prevented according tothe invention.

In a particularly preferred configuration each of the gap sections isconfigured as a gap. The gaps may partially merge into one another ormay be configured separate from one another. Then the term gap sectionmay be consistently replaced by the term gap in the present application.

In a preferred configuration a substantial part of the magnetic field ofthe magnetic field source passes through at least one and in particulartwo axial gap sections formed at opposite ends between the housing andat least one of the partition units for sealing the lateral axial gaps.Through the magnetic field passing therethrough the magnetorheologicalparticles present in the axial gap are interlinked so as to obtaincomplete sealing that is also effective with high pressures.Alternatively or additionally the magnetic field may be applied to atleast one radial gap section or gap between the partition unit connectedwith the damper shaft and the housing so that when the magnetic field isactive this radial gap (gap section) is sealed as well.

In a preferred specific embodiment at least one of the gap sections isconfigured as a damping gap and at least one of the gap sections, as asealing gap. At least one of the damping gaps preferably shows a(considerably) larger gap height than does a sealing gap. The gap heightof the damping gap is in particular at least double the size or at least4 times the size or at least 8 times the size of the gap height of asealing gap. It is preferred for the gap height of a sealing gap to belarger than 10 μm and in particular larger than 20 μm and preferablybetween approximately 20 μm and 50 μm. The gap height of a damping gap,however, is preferably >100 μm and preferably >250 μm and it ispreferably between 200 μm and 2 mm gap height. In advantageousconfigurations the gap height of a damping gap may be between(approximately) 500 μm and 1 mm.

Basically all of the gap sections contribute to, or influence, thedamping. The passage through a damping gap (showing a larger gap height)may be effectively controlled by a control device so as to provide forprecise adjustment of the active braking momentum. A damping gap showinga larger gap height allows to convey a correspondingly high volume flow.

Preferably the magnetic field source comprises at least one electriccoil. It is also possible to use two, three or more electric coils forforming the magnetic field of the magnetic field source. It is alsopossible for the magnetic field source to comprise at least onepermanent magnet or for at least one permanent magnet to be attributedto the magnetic field source.

In preferred specific embodiments both of the axial ends of thepartition wall connected with the damper shaft are each configured witha (front-face) axial gap section respectively gap between the housingand the partition wall. Preferably at least a substantial part of themagnetic field of the magnetic field source passes through both of theaxial gap sections between the housing and the partition wall andprovides for sealing the two (front-face) axial gap sections. These gapsections then form the third gap section and a fourth gap section. Thenthe axial gaps on both front faces are sealed by the magnetic field.Passage control may also be influenced by controlling the strength ofthe magnetic field at these sealing gaps. However, passage is decisivelyinfluenced by the one or more damping gaps or damping gap sections.

It is also possible to use a non-rectangular partition unit. Thepartition units may for example be semicircular and be accommodated in acorresponding hemispherical accommodation in the housing. Then, gaps orgap sections will also ensue in a (partially or predominantly) axialorientation and in a (partially or predominantly) vertical orientation.In the sense of the present invention two gap sections may also beunderstood to mean sections of different orientations in a continuousgap.

Preferably two electric coils are provided which are in particular eachdisposed adjacent to the damper volume. Preferably one controllableelectric coil is associated with one axial gap each. In particular onecontrollable electric coil each is accommodated axially outwardly in thevicinity of an axial gap.

In all the configurations it is preferred for the magnetic field toextend transverse to at least one of the gap sections. In particular themagnetic field extends transverse to at least two, three or more gapsections. A magnetic field extending transverse to the gap sectionachieves a particularly strong effect. Then the magnetic field may beoriented perpendicular to the gap section. Alternately the magneticfield may extend inclined through the gap section.

It is preferred for at least one radial gap section to be configured asa damping duct and to be radially disposed between the partition unitconnected with the damper shaft and the housing. It is also possible andpreferred for at least one axial gap section to be configured as adamping duct and to be disposed axially between the partition unitconnected with the damper shaft and the housing.

Particularly preferably both the axial gaps and the radial gaps aresealed by means of the magnetic field of the magnetic field source.

Preferably at least a substantial part of the magnetic field of themagnetic field source passes through the damping duct. Particularlypreferably at least a substantial part of the magnetic field of themagnetic field source passes through all of the gap sections. A“substantial part” of the magnetic field is in particular understood tomean a proportion of >10% and preferably a proportion of more than 25%.

In all the configurations it is also possible for at least one gapsection to be sealed by means of a mechanical seal. It is the object ofthe seal to prevent or delimit mass transfer and pressure loss/pressuredrop between spaces. Such a mechanical sealant may be a mechanical sealsuch as a sealing lip, sealing strip, gasket, profiled gasket, brushseal, or an O-ring or quadring or the like. For example the gap sectionextending between the partition unit connected with the housing and thedamper shaft may be sealed by a mechanical sealant while the gap sectionbetween the partition unit connected with the damper shaft and thehousing and the axial gap sections are subjected to the magnetic fieldof the magnetic field source for setting the desired damping.

In all the configurations it is particularly preferred for the housingto comprise a first and a second end part and in-between, a center part.In particular the center part may consist of two or more separatesections. In particular at least one of the two end parts and inparticular both of the end parts accommodate one electric coil each. Theaxis of the coil is in particular oriented substantially in parallel tothe damper shaft. This achieves a compact structure which allows toobtain a high level of sealing by means of the magnetic field of themagnetic field source.

Preferably the housing consists at least substantially of a magneticallyconductive material showing relative permeability of above 100. Therelative permeability is in particular above 500 or above 1000. It ispossible for the housing to consist entirely, or substantially, or atleast for a substantial part, of such a material. Particularlypreferably at least one of the housing sections adjacent to the dampervolume consists of a magnetically conductive material.

Preferably a (separate) ring is disposed axially adjacent to theelectric coil in the housing. The ring is in particular disposed axiallybetween the electric coil and the damper volume.

It is possible for the ring and/or the electric coil to be locatedsubstantially, or nearly completely, or completely, radially furtheroutwardly than the damper volume. Preferably the ring is located axiallyadjacent to and bordering a center part of the housing. In theseconfigurations it is preferred for the ring to consist at leastsubstantially or entirely of a material showing relative permeability ofless than 10. The relative permeability of the ring material is inparticular less than 5 or even less than 2. The ring thus preferablyconsists of magnetically non-conductive materials. The ring may forexample consist of austenitic steel. The ring material shows magneticpermeability so as to reliably prohibit magnetic short-circuits of themagnetic field of the magnetic field source. In these configurations thering is in particular configured as a flat washer or a hollow cylinder.

In other configurations the ring and/or the electric coil is disposed(substantially) not adjacent to the center part of the housing. Then itis possible and preferred for the ring and/or the electric coil to bedisposed radially further inwardly and/or at least partially or entirelyadjacent to the damper volume. The ring may be configured as a hollowcylinder and in particular as a hollow cone frustum. Then the ring showsradially outwardly a thinner wall thickness than it does radiallyfarther inwardly. The cross-section of the ring shows an inclinedorientation. In these configurations the ring preferably consists of amagnetically conductive material. Then the relative permeability of thering material is preferably above 10 and particularly preferably above50 and in particular above 100. The configuration is very advantageoussince it allows to reliably prevent leakage through the (axial) gapsection in the region of the electric coil. The ring preferably showsthe shape of a cone frustum with a hollow cylindrical interior andconsists of a magnetically conductive material. An arrangement of thecoil laterally adjacent the damper volume prevents leakage in the regionof the coil, in particular with a sufficiently strong active magneticfield.

In all the configurations a magnetic sealing of the axial gaps on thefront faces increases damping. Moreover, pressure loss within the axialgap due to transfer of magnetorheological fluid is prevented.

In all the configurations it is particularly preferred to convey themagnetorheological fluid by way of relative pivoting motion of thedamper shaft and of the housing through at least one (damping) gap fromone chamber into the other chamber.

It is possible and preferred for the damper shaft to show two or morepartition units disposed distributed over the circumference. Thenpreferably two or more partition units are correspondingly configured onthe housing distributed over the circumference. Preferably the onepartition unit connected with the damper shaft interacts with apartition unit connected with the housing. A plurality of pairs ofpartition units allows to increase the maximally effective brakingmomentum.

If only one partition unit is configured on the damper shaft and onlyone partition unit is configured on the housing, the maximally feasibleswiveling angle between the damper shaft and the housing is as a ruleless than 360° or amounts to (almost) 360°. If two partition units eachare used, the maximum swiveling angle is up to (and as a rule slightlyless than) 180°. Accordingly, given four partition units on the dampershaft and the housing, swiveling angles of less than 90° or up to 90°are feasible as a rule. If high braking moments are required and only alimited swiveling angle is necessary, a suitable rotary damper can thusbe provided using simple means.

Preferably, given a pertaining number of partition units, acorresponding number of chambers or pairs of chambers are formed whereinone part thereof forms a high pressure chamber in a swiveling motionwhile another part thereof forms a low pressure chamber. Then the highpressure and low pressure chambers are preferably interconnected throughsuitable connection ducts to thus provide at all times pressurecompensation between the individual high pressure chambers respectivelythe individual low pressure chambers. The effectiveness of the entirerotary damper is not affected by these connection ducts since in theoryan identical pressure is intended to prevail at all times in all thehigh pressure chambers (low pressure chambers). It has been found,however, that suitable connection ducts allow to improve functionalityand tolerances if any can be compensated.

In preferred configurations an equalizing device with an equalizingvolume is provided. The equalizing device serves in particular to enableleakage and/or temperature compensation. The equalizing device allows toprovide for volume compensation in the case of varying temperatures.Moreover an improved long-time functionality can be ensured since asuitable equalizing volume also allows compensation of leakage loss overextended periods of time without adversely affecting functionality.

In preferred configurations of all the embodiments and configurationsdescribed above the equalizing volume is connected with the two chambers(high pressure side and low pressure side) through a valve unit. Thevalve unit is preferably configured to establish a connection betweenthe equalizing volume and a low pressure chamber and to block aconnection between the equalizing volume and the high pressure chamber.In simple configurations this functionality is provided by adouble-acting valve of a valve unit wherein both of the valves of thevalve unit close if in the adjacent chamber a higher pressure prevailsthan in the equalizing volume. This results in automatic conveying ofvolume out of the equalizing volume respectively into the equalizingvolume as the pressure in the pertaining low pressure chamber decreasesor increases.

In preferred configurations the or a part of the equalizing device isaccommodated in the interior of the damper shaft. This saves mountingspace. The damper shaft in particular comprises a hollow space in itsinterior. The hollow space is preferably accessible from (at least) oneaxial end of the damper shaft. In particular at least part of the hollowspace or the entire hollow space is formed as a round or evenlyconfigured hollow cylinder. Preferably a raceway for a dividing pistonis configured in the hollow space or hollow cylinder to separate an airchamber or fluid chamber from an equalizing volume in particular filledwith MRF. The equalizing volume is preferably connected with at leastone connection duct having at least one chamber to provide for volumecompensation e.g. in temperature fluctuations or leakage loss of MRF.

In all the configurations and specific embodiments the damper shaft maybe configured as one piece. In preferred configurations the damper shaftis configured in two pieces or three pieces or multiple pieces.Preferably the two, three or more parts can be non-rotatably connectedor coupled with one another. In a configuration where a hollow portionof the damper shaft (hollow shaft) accommodates an equalizing device asdescribed above, a junction shaft is preferably provided which isaxially connected and non-rotatably coupled with the hollow shaft. Thejunction shaft and the hollow shaft may preferably be axially screwed toone another.

In all the configurations it is preferred for at least one duct to runfrom the interior to the housing surface which duct is connected on theinside with at least one chamber and which can be closed at theoutwardly end for example by a cover. Then an external equalizing devicemay be connected from the outside as required. A hollow space that maybe present in the interior of the damper shaft may be filled up with aninsert.

Preferably the housing is provided with at least one sensor and inparticular at least one angle sensor and/or at least one displacementsensor. In preferred configurations an absolute angle sensor ordisplacement sensor and/or a relative angle sensor or displacementsensor may be provided. Then for example an imprecise absolute sensoralways provides an approximate value while following movement, therelative sensor then obtains a precise value which can then be used.Then for example in the case of a switch-off there will always be an“approximately” correct value for first starting controlling.

The housing and in particular an outside surface of the housing ispreferably provided with at least one mechanical stopper interactingwith the damper shaft and providing an effective rotational anglelimiter without having the partition walls go into lockout. Thisfacilitates the mechanical design of the strength of the components.

In all the configurations it is preferred to provide a temperaturesensor for capturing the temperature of the magnetorheological fluid.Such a temperature sensor allows to provide for controlling adapted tothe presently prevailing temperature so that the rotary damper alwaysshows the same performance independently of the temperature of themagnetorheological fluid.

In all the configurations it is particularly preferred for the dampingcircuit of the magnetorheological fluid to be disposed completely insidethe housing. This allows a particularly simple and compact structure.

Preferably an angle sensor is provided for capturing a measure for anangular position of the damper shaft. This enables angle-dependentdamping control. For example increased damping may be set near an endposition.

In all the configurations it is preferred to provide a load sensor forcapturing a characteristic value of a rotational force on the dampershaft. This then allows load-dependent control for example to optimallyutilize the damper travel still available.

In all the configurations it is also preferred that at least one sensordevice is comprised including at least one position and/or distancesensor for capturing a position and/or distance from surroundingobjects. The control device is preferably configured and set up tocontrol the rotary damper in dependence on the sensor data from thesensor device.

An apparatus according to the invention as the chassis componentcomprises at least one rotary damper as described above. An apparatusaccording to the invention may in particular be configured as astabilizer of a motor vehicle. An apparatus according to the inventioncomprises two units movable relative to one another and at least onerotary damper as described above.

In a preferred specific embodiment the apparatus comprises a controldevice and a plurality of interconnected rotary dampers.

In particular an apparatus having multiple interlinked rotary dampersallows a great variety of applications.

In all the configurations the chassis component allows a great varietyof uses. A considerable advantage of the chassis component according tothe invention consists in the fact that the displacing device of therotary damper is provided with magnetorheological fluid as a workingfluid. Thus the magnetic field of the magnetic field source can becontrolled and set by a control device in real time, i.e. in a matter ofmilliseconds (less than 10 or 20 ms) and thus the braking momentumapplied on the damper shaft is also set in real time.

The rotary damper comprises a displacing device. The displacing devicecomprises a damper shaft and rotating displacing components. The rotarymotion of the damper shaft can be damped (monitored and controlled). Thedisplacing device contains magnetorheological fluid as a working fluid.At least one control device is associated. Furthermore at least onemagnetic field source is provided respectively comprised including atleast one electric coil. The magnetic field source can be controlled viathe control device and the magnetorheological fluid can be influencedvia the magnetic field for setting and adjusting the rotary motion ofthe damper shaft.

Such a chassis component with a rotary damper is very advantageous in avehicle. One advantage is that the displacing device is provided withmagnetorheological fluid as a working fluid. Thus the magnetic field ofthe magnetic field source can be controlled and set by a control devicein real time, i.e. in a matter of milliseconds (less than 10 or 20 ms)and thus the braking momentum applied on the damper shaft is also set inreal time if the rotary damper is intended to apply a specific brakingmomentum. The structure of the rotary damper is simple and compact andrequires a small number of components so that the chassis component withthe rotary damper is inexpensive in manufacturing and provided to beincorporated into the vehicle.

The structure of the chassis component according to the invention issimple and compact and requires a small number of components so as toprovide a chassis component inexpensive in manufacturing even in(large-batch) series production. In all the configurations it ispossible and preferred for the magnetic field source to comprise atleast one (additional) permanent magnet. A permanent magnet allows togenerate a controlled static magnetic field for example to generate orprovide a base momentum of a specific level. This magnetic field of thepermanent magnet may be intentionally boosted or weakened by means ofthe electric coil of the magnetic field source so that the magneticfield can preferably be set and adjusted as desired between 0 and 100%.This results in a braking momentum which can also preferably be setbetween 0% and 100%. If the magnetic field is switched off or reduced toa low value, a weak or very weak base momentum can be generated.

It is possible and preferred to permanently change the magnetization ofthe permanent magnet by at least one magnetic pulse of an electric coil.In such a configuration the permanent magnet is influenced by magneticpulses of the coil so as to permanently change the field strength of thepermanent magnet. The permanent magnetization of the permanent magnetmay be set by the magnetic pulse of the magnetic field generating deviceto any desired value between zero and remanence of the permanent magnet.The magnetization polarity can be changed as well. A magnetic pulse forsetting the magnetization of the permanent magnet is in particularshorter than 1 minute and preferably shorter than 1 second andparticularly preferably the pulse length is less than 10 milliseconds.

The effect of a pulse is that the shape and strength of the magneticfield is maintained permanently in the permanent magnet. The strengthand shape of the magnetic field may be changed by at least one magneticpulse of the magnetic field generating device. A damped magneticalternating field can demagnetize the permanent magnet.

A material suitable for such a permanent magnet showing changeablemagnetization is for example AlNiCo but other materials showingcomparable magnetic properties may be used as well. Moreover it ispossible to manufacture instead of a permanent magnet the entirety orparts of the magnetic circuit from a steel alloy showing strong residualmagnetization (high remanence).

It is possible to generate with the permanent magnet, a permanent staticmagnetic field which can be superposed by a dynamic magnetic field ofthe coil for setting the desired field strength. The magnetic field ofthe coil may be used to change the present value of the field strengthas desired. Alternately, two separately controlled coils may be used.

In all the configurations it is preferred for the permanent magnet toconsist at least in part of a magnetically hard material whose coercivefield strength is above 1 kA/m and in particular above 5 kA/m andpreferably above 10 kA/m.

The permanent magnet may at least in part consist of a material showinga coercive field strength of less than 1000 kA/m and preferably lessthan 500 kA/m and particularly preferably less than 100 kA/m.

In all the configurations it is preferred to provide at least one energystorage device. The energy storage device is in particular rechargeable.The energy storage device is in particular mobile and may be disposedon, or even incorporated in, the rotary damper. The energy storagedevice may for example be configured as an accumulator or a battery.

The rotary damper may also serve to damp rotary motion between twocomponents so as to damp for example rotary motion of a car door or atailgate of a motor vehicle or a gull-wing door or a hood (bonnet). Itmay also be employed in a machine to damp its rotary motions.

The presently described chassis component may be extremely compact instructure and very inexpensive in manufacture. The magnetic sealing ofthe chassis component by way of magnetorheological fluid allows toachieve a high-level sealing effect. High maximum pressures of 100 barand more are achievable.

The force path of the rotary damper in the chassis component accordingto the invention may be controlled continuously, variably and very fastby way of the electric current applied to the electric coil.

The chassis component may advantageously be linked to a computer to setand adjust the chassis component and/or to protocol its operation. Thenthe ideal settings and adjustments are programmed in the computer.

There may also be provided motion conversions between rotative andlinear or to other motion forms by lever. Use is also feasible in mineblast protection seats. The invention may be used for chassis damping ina variety of vehicles. Any commonly used linear dampers may optionallybe replaced by the rotation dampers which are in direct or indirectconnection with parts of the chassis. The rotation damper of the chassiscomponent may for example be attached in a pivot point of the triangularsuspension or transverse control arm and be operatively coupledtherewith. Preferably the rotary damper doubles as the point of supportfor the pivoting chassis part. This achieves a very compact andinexpensive structure. Moreover due to the mass thus attached at thevery bottom the overall center of gravity of the vehicle shifts towardthe road surface which is advantageous in terms of dynamics. Asuspension strut is always oriented upwardly, thus raising the center ofgravity. Thus the suspension strut also reduces the trunk (boot) volumeor in future electric vehicles, the horizontal space for thebatteries/accumulators. Such a chassis component with a rotation damperof a flat structure is very advantageous.

The spring may be a torsion spring, coil spring, leaf spring or air/gasspring in functional connection with the chassis parts.

It may be employed in a stabilizer with the rotary damper disposedbetween two components of a stabilizer which are adjustable and inparticular contra-rotatable relative to one another. One of thecomponents is coupled with a first side and the other of the components,with the other side so as to allow controlled damping, completedecoupling, or adjusting relative rotation of the stabilizer componentsrelative to one another via the rotary damper. This provides an activestabilizer suitable for setting to a variety of different ridingconditions. For example if a wheel passes over a pothole, one of thewheel sides may be decoupled from the other wheel side so as to reducethe vehicle body motions and increase comfort. In riding through curves,rolling may be stabilized by controlled damping or crossing of the twostabilizer halves (minimizing the roll angle of the vehicle body). Avariable distribution of the wheel/road contact loads between the insideand outside wheels is thus likewise possible. Preferably the two halvesare coupled in the zero-current state (e.g. by permanent magnet orremanence in the magnetic field circuit) and they are decoupled asdesired by means of electric current.

The features according to the invention allow to achieve high pressuredrops even in the case of complex contours and contour transitions,involving little technical work and costs.

Another chassis component according to the invention comprises a rotarydamper, a housing, at least one magnetic field source and a dampervolume provided with magnetorheological fluid and subdivided by at leastone partition unit connected with a damper shaft into at least two(variable) chambers. Gap sections are formed between the partition unitand the housing. At least one magnetic field source with at least onecontrollable electric coil is comprised. The housing, the magnetic fieldsource and the partition unit are configured and set up for a magneticfield of the magnetic field source to flow through the significant gapsections between the partition unit and the housing. The strength ofdamping is in particular adjusted in dependence on the strength of themagnetic field.

Preferably at least one partition unit is provided that is connectedwith the housing. A gap section is in particular configured between thepartition unit and the shaft through which the magnetic field of themagnetic field source can flow.

The partition unit connected with the shaft is in particular configuredas a swiveling vane.

Advantageously a radial damping gap and two axial sealing gaps areconfigured between the swiveling vane and the housing.

A method according to the invention for damping movements of a chassiscomponent with a rotary damper provides for the chassis componentrespectively the rotary damper of the chassis component to comprise atleast one magnetic field source and a damper volume provided withmagnetorheological fluid and subdivided into at least two chambers by atleast one partition unit connected with a damper shaft. Gap sections areformed between the partition unit and the housing. A magnetic field ofthe magnetic field source flows (as required) through the significantgap sections between the partition unit and the housing to influence thedamping and in particular to set and adjust the strength of damping. Themagnetic field source comprises at least one controllable electric coiland controls the damping strength by way of the strength of the magneticfield. The controlled magnetic field acts simultaneously in thesignificant gap sections. This controls not only the damping but itlikewise controls the sealing strength, thus changing the base momentum.Thus, the base momentum is considerably lower in the case of weakmagnetic field strengths.

Basically, permanent magnets for sealing the gap with MRF may beattached in any place as is described in U.S. Pat. No. 6,318,522 B1. Onepermanent magnet or multiple permanent magnets may be employed.Basically these act as do mechanical (rubber) sealing members. This isalso feasible on a pivoting component including in the interior pressurearea. This sealing is also feasible for rectangular surfaces. Such asealing is not or not readily possible with electric coils which must beincorporated virtually “centrally” in the magnetic circuit. Preferablyin a pressureless area and with fixed cables and round as a windingpart. Attachment is thus much more complicated than in the case ofpermanent magnets. Particularly if the lowest possible quantity ofelectric coils is intended to influence more than one gap or all of thegaps. With the present invention the coils are not subjected to pressureand their winding may be normal. In total the construction is verysimple and inexpensive in manufacture. Moreover the base momentum varieswith the strength of the generated magnetic field. In the case of a verylow or absent magnetic field the friction is set very low since the gapsare large.

In all the configurations the swiveling angle can be varied by means ofthe quantity of partition units or the quantity of vanes. In the case ofone partition unit, a swiveling angle of ca. 300 degrees is achieved.Two partition units provide for a swiveling angle of ca. 120 degrees andwith four vanes, ca. 40 degrees. The more partition units are provided,the higher is the transmissible momentum.

It is also possible to series-connect, i.e. to cascade, two or morepartition units (swiveling vanes). One single partition unit allows aswiveling angle of ca. 300 degrees. Connecting the output shaft with thehousing of a second rotary damper enables 600 degrees on the outputshaft of the second rotary damper. In applications requiring more than300 degrees the swiveling angle can thus be increased. Providingsuitable nesting the realization will save on mounting space.

The invention is also directed at a chassis component which is e.g.configured as a controllable stabilizer or antiroll stabilizer for awheel axle of a vehicle and in particular a motor vehicle, wherein sucha stabilizer comprises at least one rotary damper and (at least) twostabilizer rods of which one first stabilizer rod is connected by itsdistal end at least indirectly with a first wheel of the vehicle and ofwhich the second stabilizer rod is connected by its distal end at leastindirectly with a second wheel (in particular on the same wheel axle) ofthe vehicle, wherein one of the two stabilizer rods is connected with adamper shaft of the rotary damper and the other of the two stabilizerrods, with the housing of the rotary damper and is configured to damp arelative rotary motion of the two stabilizer rods to one another. Therotary damper has a damper volume with magnetorheological fluid as aworking fluid and at least one magnetic field source to damp a dampingof the rotary motion of the two stabilizer rods relative to one another.

In a specific embodiment of this stabilizer the rotary damper comprisesa displacing device with at least two partition units which subdividethe damper volume into at least two variable chambers, and wherein atleast one of the partition units comprises a partition wall connectedwith the housing, and wherein at least one of the partition unitscomprises a partition wall connected with the damper shaft. Preferably agap section is configured in the radial direction between the partitionunit connected with the housing and the damper shaft. In particular agap section is configured in the radial direction between the partitionunit connected with the damper shaft and the housing. At least one gapsection is configured in particular in the axial direction between thepartition unit connected with the damper shaft and the housing.Preferably at least a substantial part of the magnetic field of themagnetic field source passes through at least two of the indicated gapsections.

Further advantages and features of the present invention can be takenfrom the description of the exemplary embodiments which will bediscussed below with reference to the enclosed figures.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The figures show in:

FIG. 1 a stabilizer as a chassis component according to the invention;

FIG. 2 a bicycle having chassis components according to the invention;

FIG. 3 a sectional detail view of a rotary damper of a chassis componentaccording to the invention;

FIG. 4 a schematic section of a rotary damper for a chassis componentaccording to the invention;

FIG. 5 a section of another rotary damper of a chassis componentaccording to the invention;

FIG. 6 a sectional detail view of another exemplary embodiment of arotary damper of a chassis component according to the invention;

FIG. 7 a section of the rotary damper of FIG. 6;

FIG. 8 a section of another rotary damper of a chassis componentaccording to the invention;

FIG. 9 a section along the line B-B in FIG. 8;

FIG. 10 an enlarged detail of FIG. 9;

FIG. 11 a cross-section of a rotary damper of a chassis componentaccording to the invention with the magnetic field curve inserted;

FIG. 12 another cross-section of the rotary damper of FIG. 11 with themagnetic field curve inserted;

FIG. 13 a schematic cross-section of a rotary damper of a chassiscomponent according to the invention;

FIG. 14 different views of a damper shaft for a rotary damper of achassis component according to the invention;

FIG. 15 a section of a rotary damper of another chassis componentaccording to the invention;

FIG. 16 a schematic cross-section of a rotary damper of another chassiscomponent according to the invention;

FIG. 17 a rotary damper of a chassis component according to theinvention with a torsion rod;

FIG. 18 a sectional detail view of a rotary damper of another chassiscomponent according to the invention;

FIG. 19 a cross-section of the rotary damper of the chassis component ofFIG. 18;

FIG. 20 a longitudinal section of the rotary damper of the chassiscomponent of FIG. 18; and

FIG. 21 an alternative embodiment of the rotary damper of a chassiscomponent according to FIG. 18.

FIG. 1 shows an exemplary embodiment of a chassis component 100according to the invention which is configured as a stabilizer for amotor vehicle. Basically, different embodiments are possible.

DESCRIPTION OF THE INVENTION

In a simple configuration one single rotary damper 1 is provided,presently the rotary damper 1 b. Then the components designated 1 a and1 c only serve to support the two stabilizer rods 101 and 102 on thebody of a vehicle such as a passenger car or a truck or another vehicleand may have no other function. Use is possible also in special-purposevehicles or tanks or the like.

In a particularly simple configuration the first stabilizer rod 101 isconnected by its distal end 111 directly or indirectly and at leastindirectly, with a first wheel of the vehicle. The second stabilizer rod102 is correspondingly connected by its distal end 112 with a secondwheel of the vehicle.

The two stabilizer rods 101 and 102 are connected with the rotary damper1 b wherein one of the two stabilizer rods 101, 102 is non-rotatablycoupled with the damper shaft 3 (see FIG. 3) and wherein the other ofthe two stabilizer rods 102, 101 is connected with the housing 12 (seeFIG. 3).

The rotary damper 1 b is rotatably connected with the vehicle body. Therotary damper 1 b serves to damp a rotary motion of the two stabilizerrods 101, 102 to one another. Such a relative motion occurs while amotor vehicle is traveling in a straight line e.g. if only one wheelrides over an obstacle or through a pothole, thus lifting or loweringcorrespondingly. If the two stabilizer rods 101, 102 were non-rotatablycoupled, the other of the stabilizer rods would perform a correspondingpivoting motion. In straight-line traveling, unsteady ridingcharacteristics may follow which is why in these cases a decoupling orat least weaker coupling of the two wheels on a wheel axle can beadvantageous. In riding through curves a coupling is desired though.

The controllable rotary damper 1 b as a chassis component 100 isadvantageous since it enables a controllable (sensitive) couplingintensity of the two stabilizer rods 101, 102. Depending on theintensity of the magnetic field of a magnetic field source 8 of therotary damper the magnetorheological fluid in the displacing device 2 ofthe rotary damper 1 b can be influenced to set and adjust the couplingintensity of the two stabilizer rods 101, 102.

Then a (virtually) complete decoupling can be set in which only a verylow base momentum acts. Also, a (virtually) rigid connection can be setwhere only the torsional effect, which may be weak, of the stabilizerrods 101, 102 acts.

Thus the chassis component 100 allows to decouple the left from theright wheel side. A multi-functional spring rate switching and/or alevel adjustment can be achieved. Level adjustment is also possible byapplying the sawtooth principle and the freewheel principle, utilizingthe vehicle body movement.

In a first embodiment, rotational forces of up to 1,000 Nm are achievedand exceeded, with the maximum rotational angle being larger than 25°and may be 30° and more.

One advantage is that a simple structure is given. Conveniently therotary damper forms a direct MRF coupling, i.e. two actuator componentspivoting relative to one another generate the rotational force withoutusing a transmission. The system is simple, sturdy, and without play.The weight required is relatively low at ca. 2,500 to approximately4,000 g. The length of the rotary damper given a diameter of(approximately) 85 mm is ca. 150 mm. The operating voltage may beselectable.

It is very advantageous that switching times=<10 ms can be achieved inswitching from minimum to maximum. This allows to respond e.g. topotholes during traveling. The operating range may be variable and in anexample it is between approximately 50 Nm and 1.000 Nm and it may belarger or smaller.

Possible is not only maximum coupling or releasing, but any desirednumber of (intermediate) switching positions can be selected by way ofvarying the electric current.

In another embodiment three rotary dampers 1 are employed on the chassiscomponent 100 namely, the rotary dampers 1 a, 1 b and 1 c. The rotarydamper 1 b operates as described above and selectively couples the twostabilizer rods 101, 102 to one another, more or less non-rotatably.

The two other rotary dampers 1 a and 1 c are attached to the vehiclebody by their housing. Therefore the rotary dampers 1 a and 1 c canundertake supporting the stabilizer rods 101 and 102. The stabilizer rod101 forms the damper shaft of the rotary damper 1 a and the stabilizerrod 102 forms the damper shaft of the rotary damper 1 c. This allows toselectively fix the stabilizer rods 101 and 102 to the positions of therotary dampers 1 a and 1 c.

When the two rotary dampers 1 a and 1 c are not energized, the couplingmay be controlled via the rotary damper 1 b as described above.

When the rotary dampers 1 a and 1 c are (fully) energized, then thedistal ends 111 and 112 of the stabilizer rod 101 and 102 can only(slightly) twist due to their torsional rigidity. Since the length up tothe pertaining distal end is short, a high spring rigidity of thetorsion spring is given.

It is also possible to energize the rotary dampers 1 a and 1 b while therotary damper 1 c is not energized. Then the torsional rigidity of thestabilizer rod 101 to the distal end 111 is low, due to the short freelength. The other wheel then has a considerably longer and thus moreflexible torsion spring which is formed by the entire stabilizer rod 102and also by the part of the stabilizer rod 101 between the rotarydampers 1 a and 1 b. Then, compression or rebound of the first wheel isdamped stronger than compression or rebound of the second wheel at thedistal end 112.

While one of the rotary dampers 1 a or 1 c is “active”, the rotarydamper is energized (couples) and transmits the rotational force to thevehicle body.

When the rotary damper 1 b is “active”, the rotary damper 1 b transmitsthe momentum from one stabilizer side to the other stabilizer side. Thelevel of the momentum depends on the electric current intensity(variable).

When the rotary dampers 1 a and 1 c are active, the force respectivelyrotational force is derived from the wheel through the pertaining damperto the vehicle body. The short lever arm acts as a supporting spring(spring rate switching).

When (only) the rotary dampers 1 a and 1 b are active, then theforce/rotational force flows starting from the wheel via the rotarydamper 1 a. A combination of a stiffer and a somewhat softerspring-/damper unit is given (spring rate switching).

Correspondingly, the rotary dampers 1 b and 1 c (only) may be active.Then there is the same function as above but laterally mirrored.

When only the rotary damper 1 b is active, a classic stabilizer functionis fulfilled wherein opening (switch-off) of the rotary damper 1 bdecouples the left wheel side from the right wheel side.

FIG. 2 shows a two-wheeled vehicle and in particular a bicycle withchassis components 100 according to the invention comprising rotarydampers 1. The rotary dampers 1 allow selectively controlling acompression of the front wheel and also of the rear wheel.

The bicycle 120 comprises two wheels 122 which are each pivotallyretained on the frame or the fork for damping shocks. The completelyswung-up position may be used for transporting the bicyclespace-efficiently. The complete swinging-up can be readily controlled.Then the pertaining wheel can be swung to the top transporting position125 with a minimum of force required. Or a mechanism is provided toprovide swinging up for transporting. First the wheel is preferablyremoved. Then the length 126 of the bicycle virtually corresponds tojust little more than the length from the handlebar to the saddle.

The maximum rotational angle 124 is limited by the bicycle due to thedesign. The chassis components are formed by a frame component (frame orfork), the rotary damper and the associated struts for receiving a wheel122.

Modern-day bicycles, particularly those with ever larger wheels/rims,require much space for transporting. Moreover, e-bikes are heavier andrequire still more space. Folding back the link forks much reduces spacerequirements. The (expensive) bicycle or several bicycles can thus betransported in an interior which is a great comfort advantage. However,the customer does not pay the price of a technically inferior solutionbut of a high-quality solution with a fully electronic chassis.

Omitting the link fork parts on the rear wheel saves weight. Omittingthe linear seals and due to the concept provides a reduced basefriction. Due to the concept and because of the seals (rotary instead oflongitudinal) an extended usable working range is provided.

The chassis component is robust and simple and offers good performance,and is furthermore lightweight and inexpensive. Visible and easilyexplained advantages also show on the shop floor. The differentconstruction results in unique features. The components may consist ofdifferent materials.

FIG. 3 shows a sectional detail view of the rotary damper of a chassiscomponent 100 which is applied in principle in the example of FIG. 1 andin the example of FIG. 2. The rotary damper 1 of the chassis component100 has a housing 12 and a damper shaft 3 configured pivotable relativeto one another. The damper shaft 3 is rotatably supported in the housing12 by means of sliding bearings 44. This housing 12 consists of threesections or housing parts, a first end part 22 and a second end part 24at the other end and in-between, a center part 23. Each of the partsrespectively each of the regions is a separate component which areconnected with one another during mounting. Alternately it is possiblefor the three housing part sections or regions to be parts of one singleor two components.

The two end parts 22 and 24 accommodate a circumferential electric coil9 each, which serve to generate the magnetic field required for damping.The internal space of the rotary damper 1 provides a damper volume 60. Adisplacing device 2 comprising partition units 4 and 5 is configured inthe housing. The partition units 4 and 5 partition the damper volume 60into two or more chambers 61 and 62. The partition unit 4 is configuredas a partition wall and fixedly connected with the housing 12. Thepartition unit 5 is likewise configured as a partition wall or aswiveling vane and is fixedly connected with the damper shaft 3.Preferably the partition unit 5 is formed integrally with the dampershaft 3. The damper volume 60 is presently filled withmagnetorheological fluid 6. The damper volume 60 is sealed outwardly bymeans of a seal 28 in the housing part 22. If a pivoting motion occurs,the partition units 4 and 5 displace the magnetorheological fluid (MRF)contained in the damper volume so that the MRF partially flows from theone into the other chamber.

The magnetic field source 8 in the housing part 22 consists of electriccoils 9 and may furthermore comprise at least one permanent magnet 39each being annular in configuration and accommodated in the housing part22. In this exemplary embodiment the two end parts are provided withelectric coils 9 and optionally also with permanent magnets 39. Thepermanent magnet 39 specifies a specific magnetic field strength whichmay be modulated through the electric coil 9 and can thus be neutralizedor boosted.

Two partition units 4 protrude radially inwardly from the housing intothe damper volume 60. The partition units 4 form partition walls andthus delimit the feasible rotary motion of the damper shaft 3 on whichtwo partition units 5 are also configured which protrude radiallyoutwardly from the damper shaft. Rotating the damper shaft 3 swivels thepartition walls 5 which thus form swiveling vanes.

The electric coils 9 in this exemplary embodiment are disposed radiallyrelatively far outwardly and are axially inwardly delimited by a ring 20that is magnetically non-conductive or poorly conductive and serves toform the magnetic field curve. The ring 20 has a hollow cylindricalshape.

These partition units 5 show connection ducts 63 which will be describedin more detail in the discussion of FIGS. 5 and 14.

FIG. 4 shows a cross-section of a simply structured rotary damper 1 of achassis component 100. The displacing device comprises just one (single)partition unit 4 which extends radially inwardly from the housing intothe damper volume 60. The interior of the housing rotatably accommodatesthe damper shaft 3 from which again only one partition unit 5 extendsradially outwardly. The partition units 4 and 5 of the displacing device2 serving as partition walls variably subdivide the damper volume 60into two chambers 61 and 62. As the damper shaft rotates in theclockwise direction the volume of the chamber 61 is reduced and thevolume of the chamber 62 is enlarged while a reversed rotary motioncauses the volume of the chamber 61 to enlarge correspondingly.

FIG. 5 shows a cross-section of another exemplary embodiment with twopartition units each attached to the housing and the damper shaft 3. Thepartition units 4 and 5 disposed symmetrically thus enable a swivelingmotion of the damper shaft 3 by nearly 180°. Between the partition units4 and 5, two chambers 61 and 61 a, and 62 and 62 a respectively areformed. As the damper shaft 3 is rotated clockwise, the chambers 61 and61 a form the high pressure chambers while the chambers 62 and 62 a arethen low pressure chambers.

To cause pressure compensation between the two high pressure chambers 61and 61 a, suitable connection ducts 63 are provided between the chambers61 and 61 a, and 62 and 62 a.

Between the radially outwardly end of the partition units 5 and theinner periphery of the basically cylindrical damper volume 60, a radialgap 27 is formed which serves as a damping duct 17. Moreover, radialgaps 26 are configured between the radially inwardly end of thepartition units 4 and the damper shaft 3. The gaps 26 are dimensioned soas to enable smooth rotatability of the damper shaft 3 and to reliablyprevent the magnetorheological particles from jamming in themagnetorheological fluid inside the damper volume 60 near the gaps 26.To this end the gap 26 must show a gap height that is at least largerthan the largest diameter of the particles in the magnetorheologicalfluid.

Such a large gap 26 of a size of approximately 10 μm to 30 μm wouldusually cause a considerable leakage flow through the gap 26. This wouldeffectively prevent high pressure build-up in the chambers 61respectively 62. According to the invention this is prevented in that amagnetic field is likewise applied on the gap 26 so that the gap 26 ismagnetorheologically sealed, at least when a braking momentum is to beapplied. This causes reliable sealing so as to largely prohibit pressureloss.

FIG. 6 shows another exemplary embodiment of a chassis component 100according to the invention with a rotary damper 1. The rotary damper 1has a damper shaft 3 rotatably supported in a housing 12. The dampershaft 3 or the housing respectively are connected with junctions 11 and13 pivotal relative to one another.

The damper volume 60 is subdivided into chambers 61 and 62 by partitionunits 4 and 5 as is the case in the exemplary embodiment according toFIG. 5.

Again the housing 12 consists of three housing sections or housingparts, the axially outwardly housing parts receiving one electric coil 9each for generating the required magnetic field.

A power connection 16 supplies the rotary damper 1 with electric energy.A sensor device 40 serves to capture the angular position. Moreover, thesensor device can capture a measure of the temperature of themagnetorheological fluid. The signals are transmitted through the sensorline 48.

The partition unit 4 is accommodated stationary in the housing 12 and ispreferably inserted into, and fixedly connected with, the housing duringmounting. To prevent magnetic short circuit in the regions of thepartition unit 4, an insulator 14 is preferably provided between thepartition unit 4 and the housing parts 22 respectively 24.

FIG. 6 shows the equalizing device 30 which comprises an air chamber 32that is outwardly closed by a cap 35. The air chamber 32 is followedinwardly by the dividing piston 34 which separates the air chamber 32from the equalizing volume 29. The equalizing volume 29 is filled withmagnetorheological fluid, providing compensation in temperaturefluctuations. Moreover the equalizing volume 29 serves as a reservoirfor leakage loss occurring during operation.

FIG. 7 shows a cross-section of the rotary damper of FIG. 6 wherein onecan recognize that pairs of opposite partition units 4 and 5 aredisposed in the housing respectively attached to the damper shaft 3.Between each of the partition units 4 and 5, chambers 61 and 61 arespectively 62 and 62 a are formed in the damper volume 60. Theinsertion of pairs of partition units 4 and 5 allows to double theactive rotational force. The equalizing volume 29 is connected through aduct 36.

The duct 36 is guided into the damper volume 60 on the edge of thepartition unit 4 so that even in the case of a maximal pivoting motionbetween the damper shaft 3 and the housing 12 a connection with theequalizing volume 29 is provided. In this configuration the equalizingvolume must be prestressed to beneath the maximum operating pressure byapplying suitable pressure on the air chamber 32. The prestress may alsobe applied by a mechanical element such as a coil spring.

FIG. 8 shows a cross-section of another exemplary embodiment of achassis component 100 according to the invention with a rotary damper 1which rotary damper is in turn provided with pairs of partition units 4and 5 each of which is connected with the housing or the damper shaft 3respectively. Again, two electric coils are provided which are invisiblein the illustration of FIG. 8 because they are respectively disposed infront of and behind the sectional plane.

Between the inner housing wall and the radially outwardly end of thepartition elements 5 a radially outwardly gap 27 is formed on which asuitable magnetic field is applied for damping. A gap 26 is formedradially inwardly between each of the inner ends of the partitionelements 4 and the damper shaft 3 which is sealed by way of a magneticfield.

Unlike in the preceding exemplary embodiment the equalizing volume isconnected centrally. The equalizing volume 29 is connected with theinterior of a partition unit 4 via the duct 36.

FIG. 9 shows the cross-section B-B of FIG. 8, and FIG. 10 shows anenlarged detail of FIG. 10. The duct 36 is schematically drawn in FIG.10 and is connected with a duct in which a valve unit 31 is disposedwhich is presently a double-acting valve unit. The valve unit 31comprises two valve heads 31 a at the opposite ends of the duct. Seals33 serve for sealing when the pertaining valve head 31 is disposed inits valve seat. The duct 36 opens into an intermediate region.

On the side where the higher pressure is prevailing the valve head 31 ofthe valve unit 31 is pressed into the pertaining valve seat. On theother side this makes the valve head 31 a lift off the valve seat andallows a free flow connection to the duct 36 and thus to the equalizingvolume 29. This enables the compensation of temperature fluctuations.Moreover, if leakage loss occurs, magnetorheological fluid istransferred out of the equalizing volume into the damper volume.

An advantage of this construction is that the equalizing volume onlyrequires a relatively low prestressing pressure of 2, 3 or 4 or 5 barsince the equalizing volume is always connected with the low pressureside and not with the high pressure side of the rotary damper. Thisconfiguration reduces the loads and stresses on the seals and increaseslong-term stability. If the equalizing volume is connected with the highpressure side, a prestressing pressure of 100 bar and more may beuseful.

FIGS. 11 and 12 show cross-sections of a rotary damper 1 of a chassiscomponent 100 illustrating different cross-sections. FIG. 11 shows across-section illustrating the partition units 4 connected with thehousing in section. The magnetic insulator between the housing sideparts 22 and 24 and the partition wall 4 causes the inserted curve ofthe magnetic field line. The magnetic field lines pass through theradially inwardly gap 26 between the inner end of the partition units 4and the damper shaft 3 where they thus reliably seal the gap. When themagnetic field is switched off, the damping is reduced, and a weak basefriction results.

In the section according to FIG. 11 one can also recognize the slidingbearings 44 for supporting the pivot shaft and the seals 28 for sealingthe interior.

FIG. 12 shows a cross-section of the rotary damper 1 of a chassiscomponent 100, wherein the section passes through the damper shaft 3 anda partition unit 5 connected therewith. The other of the partition units5 connected with the damper shaft 3 on the opposite side is shown not insection. FIG. 12 also exemplarily shows the curve of a magnetic fieldline. It becomes clear that the axial gaps 25 between the partition unit5 and the housing parts 22 and 24 are sealed by the magnetic field.Furthermore, the radial gap 27 between a radially outwardly end of thepartition unit 5 and the housing is also exposed to the magnetic fieldso that the magnetorheological particles interlink, sealing the gap.

FIG. 13 shows another schematic cross-section not to scale of a damperdevice 1 of a chassis component 100 wherein the top half shows a sectionof the damper shaft 3 and the partition unit 5 connected therewith whilethe bottom half shows a section of the partition unit 4 connected withthe housing. Magnetic field lines are exemplarily drawn. Between thepartition unit 4 and the damper shaft there is a narrow gap 26preferably showing a gap height between approximately 10 and 50 μm. Inthe axial direction the partition unit 4 lies closely against thelateral housing parts. Between the partition unit 5 and the housing 12there is a radial gap 27, and on the two axial front faces, an axial gap25 each.

As a rule the axial gaps 25 show a considerably lower gap height thandoes the radial gap 27. The gap width of the axial gaps 25 is preferablylike the gap width of the radial gaps 26 and is preferably betweenapproximately 10 and 30 μm. The radial gap width 27 is preferablyconsiderably larger and preferably lies between approximately 200 μm and2 mm and particularly preferably between approximately 500 μm and 1 mm.

As the damper shaft 3 swivels, the volume of a chamber decreases andthat of the other chamber increases. The magnetorheological fluid mustsubstantially pass through the gap 27 from the one into the otherchamber. This gap 27 serves as a damping duct 17. As can be clearly seenin FIG. 13, the magnetic field lines pass through the damping duct 17 soas to allow to generate a variable flow resistance therein.

The axial gaps 25 are likewise sealed by the magnetic field, at any ratewhen its magnetic field is made strong enough so that it is no longerguided through the damper shaft 3 alone. It has been found that withincreasing strength of the magnetic field the entire magnetic field isno longer guided through the damper shaft 3 but it also passes axiallythrough the axial gap 25 and thus, with increasing strength, seals theentire axial gap 25. A suitable field strength seals accordingly.

As has been described above, in this case the magneticallynon-conductive rings 20 serve to prevent a magnetic short circuit at theelectric coil 9.

FIG. 14 shows different views of the damper shafts 3 equipped with twopartition units, the partition units 5 and 5 a being diagonally opposedso as to show a symmetric structure. FIG. 14 shows the two connectionducts 63 each interconnecting two opposite chambers 61 and 61 arespectively 62 and 62 a. To enable pressure compensation between thetwo high pressure chambers and the two low pressure chambers, whilepressure exchange or fluid exchange of a high pressure chamber and a lowpressure chamber is only possible through the damping duct 17.

FIG. 15 shows a cross-section of a rotary damper 1 of another chassiscomponent 100. This rotary damper and thus the chassis component 100 areparticularly small in structure. The rotary damper 1 of FIG. 15 may beemployed in all the exemplary embodiments and its structure is basicallythe same. The partition units 4 connected with the housing can be seenin section. The magnetic insulator 14 between the housing side parts 22and 24 and the partition wall 4 causes a curve of the magnetic fieldlines similar to FIG. 11. When the magnetic field is switched off, thedamping is again reduced and a weak base friction results. The ring 20is configured magnetically conductive to ensure safe sealing of thelateral axial gaps 26 in the region of the partition element 5. Sealingis safely obtained if a sufficient magnetic field strength is present.Again, as in FIG. 11, the sliding bearings 44 for supporting the pivotshaft and the seals 28 for sealing the interior can be recognized.

The electric coils 9 are radially arranged in the region of the dampervolume. In the region of the swiveling vane the frusto-conical shape ofthe rings 20 provided with a hollow cylinder leads to a secure sealingalso of the lateral axial gaps 26. The rings 20 presently consisting ofa magnetically conductive material cause reliable sealing of the axialsealing gaps 26 in the region of the swiveling vane respectivelypartition elements 5.

FIG. 16 shows a variant similar to FIG. 7, wherein again, two partitionunits each are attached to the housing and the damper shaft 3. Thepartition units 4 and 5 disposed symmetrically thus enable a pivotingmotion of the damper shaft 3 by almost 180°. Between each of thepartition units 4 and 5 two high pressure chambers and two low pressurechambers each are formed. The partition units 4 and 5 are configuredrounded and flow-optimized so as to prevent flow separation and thusprevent undesirable sediments from the magnetorheological fluid. Anequalizing device 30 comprising an equalizing volume 29 is alsoprovided.

FIG. 17 finally shows another exemplary embodiment wherein the rotarydamper 1 of the chassis component 100 is additionally equipped with aspring in the shape of a torsion bar. The chassis component may forexample be employed in a motor vehicle on a stabilizer. The damper shaftis coupled with one side and the housing, with the other side so thatrelative motion or relative rotation of the stabilizer componentsrelative to one another can be controlled to be damped via the rotarydamper 1. The components may be adjustable and also provided forcomplete decoupling. This provides an active stabilizer which may be setand adjusted for different riding conditions.

Furthermore, the damper shaft 3 in FIG. 17 is hollow. The spring in theshape for example of a torsion bar is disposed in the interior of thedamper shaft so as to enable resetting by way of the spring force of thespring 47.

FIG. 18 shows a sectional detail view of a rotary damper 1 of anotherchassis component 100 wherein the rotary damper 1 of the chassiscomponent 100 operates basically the same as does e.g. the rotary damperof the chassis component 100 according to FIG. 3. Therefore, to theextent possible the same reference numerals are used, and the foregoingdescription applies identically also to the rotary damper 1 of thechassis component 100 of the FIGS. 18-20, unless the description iscontrary or supplementary or the drawings show something different. FIG.21 shows a variant of the rotary damper 1 of the chassis component 100according to FIG. 18.

The rotary damper 1 of the chassis component 100 of FIG. 18 is likewiseprovided with a housing 12 and a damper shaft 3 which are configuredpivotable relative to one another. The damper shaft 3 is rotatablysupported in the housing 12 by means of roller bearings 44. The dampershaft 3 in its entirety is configured in three parts as will bediscussed with reference to FIG. 20.

The housing 12 comprises a first end part 22 and a second end part 24 atthe other end thereof, and disposed in-between, a center part 23. Bothends also accommodate external housing parts 12 a with screwingapertures. The radially outwardly housing part 12 a shows a non-roundcoupling contour 70 with recesses in the region of the end of thereference numeral line. Multiple recesses distributed over thecircumference form the non-round coupling contour which allowsnon-rotatable connection with further components.

The two end parts 22 and 24 accommodate a circumferential electric coil9 each, which serve to generate the magnetic field required for damping.

As in all the exemplary embodiments, the magnetic field is controllable.As in all the exemplary embodiments and configurations, a strongermagnetic field generates stronger damping (braking action).Simultaneously the stronger magnetic field also achieves better sealingof the gaps 25, 26 and 27 (see the schematic diagram of FIG. 13).Reversely, all the exemplary embodiments and configurations provide forsetting and adjusting weaker damping (braking action) by way of a weakermagnetic field. Concurrently the sealing effect at the gaps 25 to 27 isweaker with a weaker magnetic field. This results in a lower basemomentum acting without a magnetic field. The sealing effect of the gaps25 to 27 is low without a magnetic field. This allows to provide a widesetting range as it is not possible in the prior art. The ratio of themaximal rotational force (or maximal braking action) to the minimalrotational force (or minimal braking action) within the providedswiveling angle or within the working area is very large and larger thanin the prior art.

In conventional chassis components with rotary dampers, however, theminimal rotational force is already high if a high maximal rotationalforce is to be generated. The reason is that the seals of the gaps mustbe configured so as to ensure reliable or at least sufficient sealingincluding in the case of high active pressures. Reversely, in rotarydampers of chassis components intended to have a low braking momentum inidling, just a weak maximal rotational force is achieved since the sealsare configured so as to produce low friction. In the case of higheffective pressures this causes considerable leakage flow which stronglydelimits the maximally possible rotational force.

The internal space of the rotary damper 1 provides a damper volume. Adisplacing device 2 comprising partition units 4 and 5 is configured inthe housing. The partition units 4 and 5 partition the damper volume 60into two or more chambers 61 and 62. The partition unit 4 is configuredas a partition wall and fixedly connected with the housing 12. Thepartition unit 5 is likewise configured as a partition wall or aswiveling vane and is fixedly connected with the damper shaft 3.Preferably the partition unit 5 is formed integrally with the dampershaft 3. The damper volume 60 is presently filled withmagnetorheological fluid 6. The damper volume 60 is sealed outwardly bymeans of a seal 28 in the housing part 22. If a pivoting motion occurs,the partition units 4 and 5 displace the magnetorheological fluid (MRF)contained in the damper volume so that the MRF partially flows from theone into the other chamber. A connection duct or equalizing duct 63serves for pressure compensation between the chambers 61 and 61 a. Asuitable second connection duct 63 a (see FIG. 20) serves for pressurecompensation between the chambers 62 and 62 a.

The rearwardly end in FIG. 18 also shows a valve 66 through whichcompressible fluid is filled into the equalizing device 30. Nitrogen isin particular used. The valve 66 may for example be incorporated in ascrewed-in top or cap.

The front end in FIG. 18 shows, outside of the housing 12 of the rotarydamper 1 of the chassis component 100, a mechanical stopper 64 whichmechanically limits the feasible pivoting range to protect the swivelingvanes inside against damage.

The magnetic field source 8 in the housing part 22 presently consists ofelectric coils 9 each being annular and accommodated in the housing part22. In this exemplary embodiment both of the end parts are provided withelectric coils 9. A controller may predetermine the magnetic fieldstrength.

Two partition units 4 protrude radially inwardly from the housing intothe damper volume 60. The partition units 4 form partition walls andthus delimit the feasible rotary motion of the damper shaft 3 on whichtwo partition units 5 are also configured which protrude radiallyoutwardly from the damper shaft. Rotating the damper shaft 3 swivels thepartition walls 5 which thus form swiveling vanes. The chambers 61 and61 a are reduced accordingly (see FIG. 19) or increased again.

FIG. 19 also shows four air relief valves inserted in a prototype toachieve faster filling and draining and (all of) which may not have tobe realized.

As FIG. 20 also shows, the electric coils 9 in this exemplary embodimentare radially disposed radially relatively far outwardly and are axiallyinwardly delimited by a ring 20 that is magnetically non-conductive orpoorly conductive and serves to form the magnetic field curve. The ring20 has in particular a hollow cylindrical shape.

In the complete longitudinal section according to FIG. 20 the equalizingdevice 30 can be seen which is accommodated in the interior of thedamper shaft 3. The equalizing device 30 comprises an equalizing volume29 filled with MRF, which is separated from the air chamber 32 by amovably disposed dividing piston 34. Both the air chamber 32 and alsothe dividing piston 34 and the equalizing volume 29 are accommodatedinside a hollow cylindrical takeup space 30 a entirely in the interiorof the damper shaft 3. The hollow cylinder 30 a is closed at the axiallyoutwardly end by a top with the valve 66. This configuration allows aparticularly compact, space-saving structure with only very few partsprotruding from the rotary damper 1 which is generally substantiallycylindrical. This increases the range of options as to installation andapplication.

In FIGS. 18 to 20 the equalizing device 30 is connected through ducts(not shown) with the duct 72 which is closed by a cover 71. This allowsto optionally couple an external equalizing device 30 and to insert aninsert member in the interior to largely fill the volume of the hollowcylinder 30 a. This allows e.g. a particularly wide range of temperaturecompensation. It is also possible to ensure particularly long operatingtimes even if some leakage occurs.

FIG. 20 clearly shows the presently tripartite damper shaft 3 consistingof the hollow shaft 3 a, the junction shaft 3 b and the projection 3 c.The three parts are non-rotatably coupled with one another. It is alsopossible to configure the damper shaft 3 in two parts or in one pieceonly.

FIG. 21 shows a variant of the exemplary embodiment according to FIGS.18 to 20 with a coupled external equalizing device 30. The furthercomponents may be identical. The rotary damper 1 according to FIG. 18virtually allows to remove the cover 71 and to screw on the illustratedexternal equalizing device. In the interior an air or fluid chamber 32is configured separated by a dividing piston 34 from the equalizingvolume 29 filled with MRF.

In the interior of the hollow cylinder 30 a an insert member 67 isaccommodated to void-fill the volume.

In the exemplary embodiment according to FIG. 21 two angle sensors 68and 69 are attached as well. An angle sensor 68 providing reducedprecision measures the absolute angular position and the angle sensor 69providing enhanced precision, a relative angular position. This allowsto provide a high-precision sensor system which is rugged and reliableand still works with high precision.

Overall, an advantageous rotary damper 1 is provided. In order to allowcompensation of the temperature-induced volume expansion of the MR-fluid(MRF) and the adjacent components, it is useful to provide an adequateequalizing volume.

In a specific case ca. 50 ml MRF per single actuator or rotary damper ofa chassis component 100 is required and thus for two rotary dampers, 100ml etc. for the entire system. The prestressing member is preferably anitrogen volume that is in particular prestressed at ca. 75 bar.

In this example a coil wire having an effective cross-section of 0.315mm² was used. The number of turns of 400 showed a cable fill factor ofca. 65% with 16 ohm resistance. A larger wire diameter allows to obtaina still higher coil speed.

Preferably the axial clearance of the partition walls or swiveling vanesis set. For faultless function of the actuator it is advantageous tocenter and adjust the axial position of the swiveling vane 5 relative tothe housing. To this end e.g. threaded adjusting collars may be usedwhich are brought to a central position by means of a dial gauge.

In a specific case MRF was filled up to a filled volume of (just lessthan) 75 ml MRF. For filling the MRF may be filled through theequalizing volume. By way of reciprocal movement of the swiveling vanethe MRF can be distributed within the chambers 61, 62 (pressure space)and any air pockets can be conveyed upwardly. Thereafter the system maybe prestressed with nitrogen (ca. 5 bar). Thereafter the deaerationscrews 65 on the outside of the housing 12 may be opened to let thetrapped air escape. Finally the nitrogen chamber 32 was prestressed to30 bar for initial tests in the test rig.

For the purpose of optimizing, the actuator of the chassis component 100may be taken to a negative pressure environment to better evacuate anyair pockets.

High pressures are obtained without any mechanical sealing. The rotarydamper 1 is inexpensive in manufacture, sturdy and durable.

In this specific example the braking momentum at the test rig was >210Nm. The unit is smaller in structure, weighs less, and is morecost-effective than in the prior art.

Switching times of <30 ms are possible and have been proven (full loadstep change).

The braking momentum is variable as desired. No mechanically movingparts are required. Controlling simply occurs by way of varying theelectric current or the magnetic field.

A considerable advantage ensues from the absence of mechanical seals.Thus a very low base momentum of beneath 0.5 Nm is achieved. This isachieved by controlling not only the braking momentum but simultaneouslyalso the sealing effect of the seals. On the whole there is a very lowpower consumption of just a few watts in the example.

The chassis component 100 is in particular employed as, or forms partof, a stabilizer. The chassis component 100 may also be part of abicycle. In all the cases dimensioning can be matched to the desiredforces and moments to be applied.

List of Reference Numerals:  1 rotary damper  2 displacing device  3damper shaft  3a hollow shaft  3b junction shaft  4 partition unit,partition wall  5 partition unit, partition wall  6 MRF  7 controldevice  8 magnetic field source  9 electric coil 10 magnetic field 11connection (with 12) 12 housing of 2  12a outwardly housing part 13connection (with 3) 14 insulator 15 hydraulic line 16 power connection17 damping duct 19 axis of 3, 9 20 ring in 12 22 first end portion 23center region 24 second end portion 25 gap, axial gap 26 gap, radial gap27 gap, radial gap 28 seal at 3 29 equalizing volume 30 compensatingdevice  30a hollow cylinder 31 valve unit  31a valve head 32 air chamber33 seal 34 dividing piston 35 cap 36 duct 37 energy storage device 39permanent magnet 40 sensor device 41 distance 42 seal of 23 43intermediate space 44 bearing 45 load sensor 46 arm 47 spring, torsionbar 48 sensor line 52 valve unit 53 direction of movement 54 pressureaccumulator 55 direction of arrow 60 damper volume 61 chamber 62 chamber63 connection duct  63a second connection duct 64 mechanical stopper 65deaeration screw 66 nitrogen valve 67 insert member 68 sensor 69 sensor70 non-round coupling contour 71 cover 72 duct 100  chassis component101  stabilizer rod 102  stabilizer rod 111  distal end 112  distal end120  bicycle 121  accumulator 122  wheel 123  motor 124  rotationalangle 125  top position 126  length

The invention claimed is:
 1. A chassis component with a rotary dampercomprising: a housing, a damper shaft rotatably mounted to said housing,a displacing device in said housing, and at least one magnetic fieldsource; said displacing device containing a damper volume withmagnetorheological fluid as a working fluid for influencing a damping ofa rotary motion of said damper shaft relative to said housing; saiddisplacing device including at least two partition units disposed todivide said damper volume into at least two variable chambers; at leastone of said partition units having a first partition wall connected withsaid housing; at least one of said partition units having a secondpartition wall connected with said damper shaft; a plurality of gapsections formed by said partition units, said housing, and said dampershaft, wherein: said first partition wall is disposed to form a gapsection in a radial direction between said first partition wall and saiddamper shaft; said second partition wall is disposed to form a gapsection in the radial direction between said second partition wall andsaid housing; and at least one gap section is formed in an axialdirection between said second partition wall connected with said dampershaft and said housing; at least one of said gap sections is a dampinggap and at least one of said gap sections is a sealing gap, and whereinat least one damping gap has a greater gap height than does a sealinggap; and said magnetic field source including at least one controllableelectric coil for influencing a strength of a magnetic field andconsequently a strength of damping, and wherein at least a substantialpart of a magnetic field of said magnetic field source passes through atleast two of said gap sections, simultaneously influencing said at leasttwo gap sections in dependence on a strength of the magnetic field. 2.The chassis component according to claim 1, wherein said secondpartition wall has two axial ends each forming an axial gap sectionbetween said housing and said second partition wall, and wherein asubstantial part of the magnetic field of said magnetic field sourcepasses through said two axial gap sections between said housing and saidpartition wall and provides for sealing said axial gap sections.
 3. Thechassis component according to claim 1, wherein said magnetic fieldsource is configured to generate a magnetic field that extendstransversely to at least one of said gap sections.
 4. The chassiscomponent according to claim 1, wherein at least one radial gap sectionis configured as a damping duct and is disposed radially between saidsecond partition wall and said housing and/or wherein at least one axialgap section is configured as a damping duct and is disposed axiallybetween said second partition unit and the housing.
 5. The chassiscomponent according to claim 1, wherein at least a substantial part ofthe magnetic field of the magnetic field source passes through saiddamping duct.
 6. The chassis component according to claim 1, wherein atleast one gap section is sealed by means of a mechanical sealant.
 7. Thechassis component according to claim 1, wherein the magnetorheologicalfluid is conveyed by way of relative pivoting motion of said dampershaft and said housing through at least one of said gap sections fromone of said at least two chambers into another of said at least twochambers.
 8. The chassis component according to claim 1, wherein saidsecond partition wall is one of two or more partition walls disposed onsaid damper shaft and distributed over a circumference thereof, andwherein said first partition wall is one of two or more partition wallsdisposed on said housing and distributed over a circumference thereof.9. The chassis component according to claim 1, further comprising anequalizing device with an equalizing volume connected with said at leasttwo chambers through a valve unit, wherein one of said at least twochambers is a low pressure chamber and one of said at least two chambersis a high pressure chamber, and said valve unit is configured toestablish a connection between said equalizing volume and said lowpressure chamber and to block a connection between said equalizingvolume and said high pressure chamber.
 10. A stabilizer, comprising atleast one rotary damper according to claim
 1. 11. A chassis componentwith a rotary damper comprising: a housing, a damper shaft rotatablymounted to said housing, a displacing device in said housing, and atleast one magnetic field source; said displacing device containing adamper volume with magnetorheological fluid as a working fluid forinfluencing a damping of a rotary motion of said damper shaft relativeto said housing; said displacing device including at least two partitionunits disposed to divide said damper volume into at least two variablechambers; at least one of said partition units having a first partitionwall connected with said housing; at least one of said partition unitshaving a second partition wall connected with said damper shaft; aplurality of gap sections formed by said partition units, said housing,and said damper shaft, wherein: said first partition wall is disposed toform a gap section in a radial direction between said first partitionwall and said damper shaft; said second partition wall is disposed toform a gap section in the radial direction between said second partitionwall and said housing; and at least one gap section is formed in anaxial direction between said second partition wall connected with saiddamper shaft and said housing; and said magnetic field source includingat least one controllable electric coil for influencing a strength of amagnetic field and consequently a strength of damping, and wherein atleast a substantial part of a magnetic field of said magnetic fieldsource passes through at least two of said gap sections, simultaneouslyinfluencing said at least two gap sections in dependence on a strengthof the magnetic field, and wherein said housing comprises a first endpart, a second end part, and a center part therebetween, wherein atleast one of said first and second end parts accommodates an electriccoil, with an axis of said coil being oriented substantially in parallelto said damper shaft.
 12. The chassis component according to claim 11,wherein at least one of said gap sections is a damping gap and at leastone of said gap sections is a sealing gap, and wherein at least onedamping gap has a greater gap height than does a sealing gap.
 13. Thechassis component according to claim 11, further comprising a ringdisposed axially adjacent said electric coil in said housing.
 14. Thechassis component according to claim 13, wherein said ring consists atleast substantially of a material having a relative permeability of lessthan
 10. 15. The chassis component according to claim 13, wherein saidring is disposed axially between said electric coil and said dampervolume.
 16. The chassis component according to claim 13, wherein saidring has a radially outward region with a thinner wall thickness than ina radially inward region and/or wherein said ring substantially consistsof a material having a relative permeability of above
 50. 17. A chassiscomponent with a rotary damper comprising: a housing, a damper shaftrotatably mounted to said housing, a displacing device in said housing,and at least one magnetic field source; said displacing devicecontaining a damper volume with magnetorheological fluid as a workingfluid for influencing a damping of a rotary motion of said damper shaftrelative to said housing; said displacing device including at least twopartition units disposed to divide said damper volume into at least twovariable chambers; at least one of said partition units having a firstpartition wall connected with said housing; at least one of saidpartition units having a second partition wall connected with saiddamper shaft; a plurality of gap sections formed by said partitionunits, said housing, and said damper shaft, wherein: said firstpartition wall is disposed to form a gap section in a radial directionbetween said first partition wall and said damper shaft; said secondpartition wall is disposed to form a gap section in the radial directionbetween said second partition wall and said housing; and at least onegap section is formed in an axial direction between said secondpartition wall connected with said damper shaft and said housing; andsaid magnetic field source including at least one controllable electriccoil for influencing a strength of a magnetic field and consequently astrength of damping, and wherein at least a substantial part of amagnetic field of said magnetic field source passes through at least twoof said gap sections, simultaneously influencing said at least two gapsections in dependence on a strength of the magnetic field, and acontrol device configured to control a damping of the rotary damper, andat least one sensor device including at least one position sensor and/ordistance sensor for capturing a position and/or a distance fromsurrounding objects, and wherein said control device is configured tocontrol the rotary damper in dependence on sensor data received fromsaid sensor device.
 18. A chassis component with a rotary dampercomprising: a housing, a damper shaft rotatably mounted to said housing,a displacing device in said housing, and at least one magnetic fieldsource; said displacing device containing a damper volume withmagnetorheological fluid as a working fluid for influencing a damping ofa rotary motion of said damper shaft relative to said housing; saiddisplacing device including at least two partition units disposed todivide said damper volume into at least two variable chambers; at leastone of said partition units having a first partition wall connected withsaid housing; at least one of said partition units having a secondpartition wall connected with said damper shaft; a plurality of gapsections formed by said partition units, said housing, and said dampershaft, wherein: said first partition wall is disposed to form a gapsection in a radial direction between said first partition wall and saiddamper shaft; said second partition wall is disposed to form a gapsection in the radial direction between said second partition wall andsaid housing; and at least one gap section is formed in an axialdirection between said second partition wall connected with said dampershaft and said housing; and said magnetic field source including atleast one controllable electric coil for influencing a strength of amagnetic field and consequently a strength of damping, and wherein atleast a substantial part of a magnetic field of said magnetic fieldsource passes through at least two of said gap sections, simultaneouslyinfluencing said at least two gap sections in dependence on a strengthof the magnetic field; and a control device and a plurality ofinterconnected rotary dampers.